It is known that a photographic image having ultra-high contrast can be formed by using a certain kind of silver halide, and such a technique is used in the field of photographic printing plate making.
For example, it is known to form a line image or a dot image having high contrast and high blackening density in which the image area and non-image area can be clearly distinguished, by developing a lith film containing a silver chlorobromide emulsion containing at least 50 mol % of silver chloride with a hydroquinone developer containing, as a preservative, a sulfite ion in a concentration controlled at an extremely low level, usually not more than 0.1 mol/l. Since a developer of this type is extremely susceptible to air oxidation due to the low sulfite concentration, various efforts have been made to stably maintain the developing activity.
In order to overcome the unstability in image formation according to the above-described lith development system, an image formation system is required in which a processing solution having satisfactory preservability is used to obtain ultra-high contrast. To this end, it has been proposed that a surface latent image type silver halide photographic material having incorporated therein a specific hydrazine derivative is processed with a developer having a pH of from 11.0 to 12.3 and containing 0.15 mol/l or more of a sulfite preservative (which exhibits satisfactory preservation stability) to thereby form a negative image of ultra-high contrast, having a gamma exceeding 10, as described in U.S. Pat. Nos. 4,166,742, 4,168,977, 4,221,857, 4,224,401, 4,243,739, 4,272,606, 4,311,781, 4,269,929, and 4,650,746. This new image formation system has a further advantage that not only silver chlorobromide but silver iodobromide and silver chloroiodobromide can be employed, while the conventional ultra-high contrast image formation systems are applicable only to silver chlorobromide having a high silver chloride content.
However, in the above system, if the pH of the developer is reduced or the bromide ion concentration of the developer increases as a result of processing of a large quantity of silver halide photographic materials, the photographic materials exhibit reduction of sensitivity, gamma or maximum density. Even when the volume of films to be processed is not large, if the concentration of the sulfite preservative is considerably reduced or the pH increases due to fatigue of the developer with time, an unfavorable phenomenon called black pepper frequently occurs. The term "black pepper" as used herein means black spots of fine developed silver appearing in non-image areas (unexposed areas). Although these disadvantages may be eliminated by increasing the amount of a replenisher for the developer, such a replenishment method involves an increase of cost of the developer, handling of waste liquid, and the like. A system is eagerly sought which does not cause reduction of maximum density or black pepper without increasing the amount of a replenisher.
Further, in the new image formation system, a sensitizing dye added with the aim of increasing sensitivity has remarkable influences upon gamma or black pepper appearance, as reported in JP-A-61-47943 and 62-25745 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"). JP-A-61-29837 and Japanese patent application No. 61-79533 disclose sensitizing dyes which improve black pepper without causing reduction of gamma. These dyes, however, cause color remaining after development processing when used in an amount sufficient for achieving appreciable improvement in black pepper.
In the above-described system using a hydrazine derivative, development nuclei in areas exposed to even a trace amount of light can be amplified by the hydrazine derivative so that the areas exhibit high contrast. This means that fog nuclei due to electrons generated by externally applied pressure or subcenters of the latent image intensified by the electrons are also liable to be amplified. This disadvantage in practical use of photographic systems causes the unfavorable phenomenon that areas which should not be blackened are blackened due to linear fog by pressure application (pressure marks) or sensitization of the toe by pressure application. This phenomenon will hereinafter referred to as "pressure properties".
With respect to the ultra-high contrast negative image formation system, some of the compounds represented by formula (III) hereinafter described have been disclosed in JP-A-54-40629 (corresponding to U.S. Pat. No. 4,377,634), 56-1936 (corresponding to U.S. Pat. No. 4,385,108), 56-89738, 57-129433 (corresponding to U.S. Pat. No. 4,447,522), to 57-129436 (corresponding to U.S. Pat. No. 4,429,036), 61-233734, 62-21143, 62-63932, 62-296138 and 103232. Compounds represented by formula (II) hereinafter described have been disclosed in JP-A-61-29837, 62-237445, 62-280733 and 62-280734 and also proposed as antifoggant for silver halide color photographic materials in U.S. Pat. No. 4,147,547.
The above-cited JP-A-56-1936 discloses a system in which a light-sensitive material contains a hydroquinone and a large amount (0.05 mol/Ag or more) of the compound of formula (III). JP-A-62-21143 describes that unsubstituted hydroquinone and sulfo-substituted hydroquinone improve pressure properties but, in turn, deteriorate anti-blocking properties.
In conventional hard negative image formation systems using a hydrazine derivative, the compound represented by formula (I) has been used for various purposes described in JP-A-61-29837 and 62-280734 and Japanese patent application Nos. 61-80640 and 61-24830. Further, U.S. Pat. No. 4,147,547 refers to use of the compound of formula (I) as an antifoggant for color silver halide photographic materials. The compounds of formula (II) are described in U.S. Pat. Nos. 4,272,606 and 4,429,036.
None of the above-cited publications discloses or suggests that a combination of the compound of formula (III) and the compound of formula (I) would satisfy both demands for improving pressure properties and black pepper. Further, in order to make the best use of the improving effects of the compound of formula (III) on pressure properties, a technique to improve anti-adhesion properties is also required.